The innovative mbed-based (VI)sualizer is a lab instrument for profiling solar, chemical, and grid-powered energy delivery devices. The design enables you to examine an energy source's voltage (V) and current (I) delivery ability. You can use it for a variety of other reasons as well: to calculate the load resistance into which a solar cell delivers maximum power; to measure and capture a battery's amp-hour capacity; or, using pulsatile loads, to test conventional power supply voltage regulation accuracy. The mbed module in the design accepts input data from local and remote interfaces, commands the desired load current, and monitors operating conditions.